The invention generally relates to near-surface geomorphological characterization based on remote sensing data.
Seismic exploration involves surveying subterranean geological formations for hydrocarbon deposits. A survey typically involves deploying seismic source(s) and seismic sensors at predetermined locations. The sources generate seismic waves, which propagate into the geological formations creating pressure changes and vibrations along their way. Changes in elastic properties of the geological formation reflect, refract or scatter the seismic waves, changing their direction of propagation and other properties. Part of the energy emitted by the sources reaches the seismic sensors. Some seismic sensors are sensitive to pressure changes (hydrophones), others to particle motion (e.g., geophones), and industrial surveys may deploy only one type of sensors or both. In response to the detected seismic events, the sensors generate electrical signals to produce seismic data. Analysis of the seismic data can then indicate the presence or absence of probable locations of hydrocarbon deposits.
The understanding of the surface and near-surface of a candidate region to be surveyed is paramount for such purposes as evaluating the candidate region for a potential survey and if selected for the survey, planning the survey and interpreting the results of the survey. For example, in a seismic survey in which a vibrator is to be used as the seismic source, some regions may not be suitable for the vibrator: relatively hard rock may result in point loading where only part of the baseplate of the vibrator is coupled to ground; and relatively soft ground may not support the hold down weight and thus, may compact during the sweep as well as undesirably absorb particularly high frequencies. Knowledge of the surface and near-surface may also be useful in evaluating the accessibility of the region for certain vehicles. For example, escarpments and soft ground may affect logistical access to the survey area. For post survey processing, the elastic properties of the near-surface typically are estimated for purposes of performing static corrections to the acquired seismic data.